1. Field of the Invention
The invention relates in general to single or multi-pole circuit breakers, and more particularly, to circuit breakers having an improved means of retaining their arc grid assemblies in the arc grid assembly cavity within the framework or housing of the circuit breaker.
2. Description of the Prior Art
The basic functions of circuit breakers are to provide electrical system protection and coordination whenever abnormalities occur on any part of the system. The operating voltage, continuous current, frequency, short circuit interrupting capability, and time-current coordination needed are some of the factors which must be considered when designing a breaker. Government and industry are placing increasing demands upon the electrical industry for interrupters with improved performance in a smaller package and with numerous new and novel features.
Stored energy mechanisms for use in circuit breakers of the single pole or multi-pole type have been known in the art. A particular construction of such mechanisms is primarily dependent upon the parameters such as rating of the breaker. An example of an arc chamber assembly is found in U.S. Pat. No. 4,229,630 to John A. Wafer and Alfred E. Maier, assigned to the same assignee as the present invention, hereby referred to and incorporated herein.
Circuit breakers and other equipment employing arc grid assemblies require a means for retaining these assemblies in position within a cavity provided for them within the framework or housing of the circuit breaker. In the prior art, means for retaining the arc grid assemblies within their cavities include retaining springs, screws and other fastening means such as glue. The disadvantages of these means of retaining the assemblies employed by the prior art is economic (the cost of the mechanical retaining means employed) as well as the fact that these retaining means are subject to failure. Accordingly, it would be desirable to provide a secure, reliable assembly of the arc grid assemblies within the housing or framework of the circuit breaker (within the cavity provided for the arc grid assembly within the framework of the circuit breaker) without the use of glue, screws, springs and other mechanical retaining means.